


Mistakes you shouldn't repeat

by gabsrambles



Category: Supergirl (TV 2015)
Genre: F/F
Language: English
Status: Completed
Published: 2018-11-22
Updated: 2018-11-22
Packaged: 2019-08-27 16:12:00
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,758
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16705657
Author URL: https://archiveofourown.org/users/gabsrambles/pseuds/gabsrambles
Summary: Prompt: Alex and Lena making out in secret and things are getting heavy— hearts racing and what not... Supergirl bursts in thinking her two favorite people are in danger. Embarrassing hilarity ensues.





	Mistakes you shouldn't repeat

Lena is a mistake Alex only meant to make once.

Or you know, not make at all.

But then she made it, so then it was supposed to stay in the ‘Once Only’ column.

And Alex blames the whiskey the first time, anyway. Not at all her fault. It was purely alcohol and the fact that, well, _fine_ , Lena is really, actually, very, very hot. Like, painfully so. Alex’s Big Gay Awakening happened and she only had eyes for Maggie but then that ended in a way that still makes her stomach twist achingly (how can you be so, _so_ good with someone yet have the one fundamental thing that makes you incompatible? How?) and Alex started to notice other women.

And Lena is really hot.

Like, _yes, the boss will see you now_ hot. Sam was also attractive and maybe Alex thought for a little while that was going to build into something, but Sam, all traumatised (understandably) had to get away from where everything went down.

The woman who serves Alex coffee is really cute, with dimples in her cheeks and eyes that sometimes, when Alex isn’t drowning in the self doubt she smothers with faked bravado almost every moment, she swears rake up and down her when she hands over the coffee.

Attractive women are just everywhere. They have so many qualities. Laughs, and collarbones, and legs for days. Bright eyes and curves and, well, Alex was learning she didn’t really have a _type_.

Women are hot.

Lena is exceptionally so.

But Alex kind of noticed it distantly. Because she’s Kara’s best friend and she doesn’t know Kara is Supergirl and Alex knows it isn’t the nicest thing, but she still doesn’t entirely trust Lena to any great capacity.

Alex is trying. She moved past pinning it on the last name that Alex _knows_ follows Lena like a thick coating of ash she can never entirely beat out of the cloth on her skin. But then the kryptonite. And the shady comments.

And she’s so fucking intelligent.

She is, categorically, a danger.

A really hot danger.

But that was a distant acknowledgement. Until Alex went to L-Corp to question Lena about something and Lena rolled her eyes and gave her a drink and they sat while Lena didn’t even blink as Alex fired question after question about the Kryptonite protection suit and what it all meant and then two hours had passed and they’d drunk a little too much of the whiskey and had moved to the couch and she was close and Alex hadn’t been touched since Sara and had spent the next week after it wrapped in guilt and never really got to enjoy it. Lena’s knee bumped against hers and Alex didn’t pull away and then they were kissing, Lena’s fingers against her jaw and then her palm gliding along her cheek until her fingers were in Alex’s hair.

She was a great kisser.

It was kind of annoying, that she was that attractive and intelligent and really, really good with her lips.

Something that Alex found out in more detail not long after as they pressed against her throat and then her chest and then her stomach where Lena pushed up the shirt Alex was wearing. Her fingers were fumbling with Alex’s belt and then her boots and there was a minute where they were both laughing because getting undressed isn’t actually always the sexiest thing but then Lena’s lips were on her and her tongue and Alex came embarrassingly fast.

In her defence, so did Lena when Alex pushed her onto the carpet and her hand crept up that skirt that was now bunched around Lena’s waist.

But after all the breathy moans and flushed cheeks, the awkward aftermath settled over them and Alex kind of…tugged her pants back on, gathered her jacket and skedaddled.

One time.

It was supposed to stay one time.

Except that night she didn’t sleep even with the alcohol because she was staring at the roof remembering the damp feel of Lena’s breath against her ear and the desperate canting of her hips and the needy sounds that spilled out around them and instead of feeling _sated_ Alex wanted more, legs shifting restlessly under the heat of her sheets.

But it was a _mistake_.

A one time mistake. Once. Uno. No more.

They are _not_ a good match. At all. They come from polar opposites of everything and the whole, Kara’s best friend who can be a bit shady thing. And not knowing Kara is Supergirl.

And the whole, just…the whole _thing_.

A one time mistake.

But then they all had drinks in a bar a week later, and Kara brightened next to her and Alex followed her line of sight to see Lena walking in and she was wearing a dress that should be criminal and all she did was raise one eyebrow at Alex in greeting like nothing had happened while Alex squirmed in her chair, cheeks burning, as Lena chatted with Brainy and J’Onn and Kara as if last week she hadn’t grunted “fucking _harder_ ” in Alex’s ear before Alex had done just that and Lena had—

But no. Lena was _fine_.

But then Kara was pulled away for Supergirl duties with her usual lame excuse (her sister is so badly at lying sometimes Alex wonders if the entire city knows her identity and is just humouring her) and Brainy followed her out. J’Onn got a message and was gone, and it was Lena and Alex left with all the memories of what they did rising between them.

Alex, of course, fled to the bathroom to try get herself together.

Lena followed.

And then pushed her against the gross, dirty wall and kissed her and she is genuinely that good at kissing that Alex was convinced in 0.1 second that maybe two times would be okay. Lena whispered in her ear that the bar was gross and why not go back to her place.

So they did.

And _technically_ it wasn’t really two times after that but six, but really, it was only two _occasions_ so whatever.

It turns out that Lena was hot in a _the boss will see you now_ way but also in, well, a lot of ways. The way she arched under Alex. The way she grinned right before she ducked her head to press her tongue against her. The way she went boneless after her third orgasm and just smiled lazily up at the ceiling, and then at Alex, eyes so damn _green_.

How in the morning, she made them coffee in just an over-sized hoody and her underwear, hair piled on top her head with tendrils escaping all over the place, and casually asked Alex about particle displacement in interdimensional portals and Alex’s damn heart gave a deceiving, sharp thump against her rib cage.

After the second-slash-sixth time, she didn’t even bother trying to convince herself it wasn’t going to happen again.

So now it’s been happening for a month and it’s still a mistake, probably.

Possibly.

Maybe.

Kind of.

But maybe it’s not a genuine, painful mistake, but a mistake like if you walked into the wrong class in college and sat down and figured you were there anyway so you may as well listen and it turns out it was super interesting and made you realise you shouldn’t be majoring in literature but instead biochemistry and you wouldn’t have known if not for the first mistake.

That led to something fun.

Because, and Alex has no idea how she got here of all places, Lena Luthor is _fun_. They argue over stupid science theories and one time she made a joke that was super complex but made Alex snort her wine, and when Lena laughs, it’s so loud and real and, almost… _startled,_ like she still isn’t used to doing it so genuinely.

She shows up sometimes after a night Alex has been beating up bad guys and is super sweaty and instead of being grossed out her pupils blow wide and Alex ends up against the wall. And then in the shower.

Just not alone.

They drink coffee in the soft light of morning when they both avoid the fact that they have to go to work. They eat dinner sometimes in Lena’s office and share wine in a bar down the street for Alex’s apartment.

They send each other messages with _emojis_ and Alex wonders who the hell she’s become.

They have a lot of sex.

And Alex learns she likes the way Lena _thinks_. She considers everything. It’s different to Alex, who can have a one track mind. Lena…she sees everything in grey.

They both avoid talking about what it is and telling people and they _never_ talk about Kara, but it doesn’t really matter because whatever it is is fun and sexy and Alex’s heart does that hard _thump_ more often than she wishes it would, like the great betrayer it is.

Then one night Kara’s on patrol and Alex is bored because the city is under control so she goes to L-Corp and finds Lena on the balcony with a whiskey. When Lena turns around, it’s with the skyline behind her and her face lights up, a slow smile as her gaze definitely drops down Alex’s body to meet her eyes again, that smile turning into a smirk that makes Alex’s stomach bottom out. Alex walks forward and takes the glass from Lena’s hand, their fingers over each others until Alex tugs it away and takes a slow sip, Lena’s eyes never leaving her face.

It’s been days, because they’ve been busy. They’re both always so busy.

Lena’s kiss is hungry and Alex stumbles backwards, the glass left on the railing and her hands fisting Lena’s blazer, the silk of her blouse against her knuckles. She almost falls once as they blindly make it into the office, Alex’s leather jacket on the balcony and her shirt pulled out from where it was tucked into her jeans. Lena’s hand glides over her stomach, Alex’s muscles jumping, and over her back under her shirt. Before she can fall, her ass hits Lena’s desk and Lena’s kiss doesn’t stop even as she manages to push papers to the floor that fall with a fluttering sound. The desk is cold even through her jeans but she sits on it anyway, Lena between her legs and Alex’s wrapped around her to pull her in tighter. It’s impossible to stop, and they’ve gotten so very, very good at this.

Lena’s buttons come undone slowly, their kiss slowing to match the pace and Alex can feel Lena’s heart racing against her fingers when they graze over her sternum. She pushes the shirt off her shoulders but then holds it there, trapping Lena’s arms in place and pulling her tighter against her front, the lace of her bra soft against Alex’s chest, her own shirt thrown behind them at some point. She squeezes her legs tighter, and Lena presses more firmly against her. Lena finally pulls back to gasp, her lips so red and pupils blown so wide all Alex can do is grin before pulling her back in.

There’s a thump, a sound like wind that Alex knows far too well and then an actual _yelp_.

They freeze, everything freezes, or Alex wishes it did, forever anyway, because she knows exactly who that was and what’s happening but for the shortest of moments Lena has pulled back and they are just staring at each other, wide-eyed, horrified, because surely Lena knows too.

“I’m sorry!”

Lena twists enough in Alex’s arms to see behind her, and Alex tilts just slightly to the right to look. Behind Lena, in the doorway, just like Alex knew she would be, is Kara.

Rather, Supergirl.

But right now one is just as bad as the other.

Her hand is literally clapped over her eyes and her face is redder than Alex has ever seen it and Lena’s shirt is still clutched in both of Alex’s hands against the back of her arms, and Alex very much does not have a shirt on and all Alex can feel is annoyed because this was going to be some very, very good desk sex.

“Sorry!” Kara says again.

Silence.

“Why are you here?” Lena asks.

She doesn’t move but really Alex can’t blame her because pulling away would mean having to awkwardly clasp her shirt closed in front of her and at least this way they’re both kind of covered.

Alex hates her sister.

But also, slowly, she’s realising this is awkward as hell.

But mostly, right now, she hates her sister because Lena was very much about to push her back on this desk and it was going to be amazing.

Kara’s hand is still slapped over her eyes and her other hand is held up like she could ward them away or something, and Alex may be about to hysterically laugh so she bites her lip but her smile escapes anyway.

“I heard—I just…” Kara sighs heavily, that hand holding off evil lowering to her side. “Can I look yet?”

“Sure,” Alex answers.

She drops her hand—as if she doesn’t have x-ray vision—and when she opens her eyes she yelps again and slaps her hand back. “You haven’t moved! You’re still…almost naked.”

Lena turns to look at Alex, raises her eyebrows and sees Alex’s grin. Her eyebrows rise higher. She pulls away with a sigh, and tugs her shirt together and Alex jumps off the desk, grabs her own off the floor and holds it against her front before sitting on the edge of the desk next to Lena, who’s arms are now crossed to hold her shirt together and is watching Kara with her head tilted to one side.

There’s a slight red mark blooming on her neck Alex doesn’t even remember making.

“You can look now.”

This time, Kara spreads two fingers and looks between them cautiously. “You couldn’t get dressed properly ?” she asks, before letting her hand fall away. Two high spots of colour are sill on her cheeks and she fiddles with her cape with one hand.

Alex still just wants to laugh.

“Well, I think we would both like to get back to what we were doing,” Lena says.

Kara’s mouth drops open and Alex chokes on her snicker.

“I—was that necessary?” Kara shoots at Lena.

Lena smirks. “Yes. Again—why are you here?”

Kara sighs. “I heard—I heard your heart beats. They, um…” She’s completely red again, just like before. She avoids all eye contact. “They were fast, both of them, in the same location. I thought you were in trouble.”

“Nope,” Alex says. And maybe she’s having too much fun with this, especially considering how worried she was about Kara knowing she was banging her best friend. But seriously, her sister looks like she’s about to melt through the floor. “Not in trouble.”

Kara’s gaze is on the ceiling. “I get that now.”

Silence.

Lena clears her throat.

Kara’s neck is also red.

Alex is plain grinning.

“So…we’re fine, Kara.” Alex’s head whips around to stare at Lena, eyes wide, mouth open. As does Kara’s. “You can go.”

“Kara?” Kara squeaks. Alex is squinting at Lena, who is staring straight at Kara unblinking. Looking like she’s enjoying every single part of this far too much. “Why, uh…why would you call me that?”

Of course she knew. Of course.

Luthor. Intelligent.

Of course Lena knew. She’s probably known for a very long time.

Alex’s grin is back.

Lena rolls her eyes. “Maybe we can get into that another time, Kara?”

Kara gives a high pitched laugh. “That’s not my—not my name.”

Alex looks to Kara. “I think it’s blown.”

Kara seems to deflate on the spot. “Oh. Um….”

“Another time?” Lena asks.

“Of-of course. You’ve got things to do.” Kara’s eyes widen. “Oh my god, one of which is my sister.”

And with that, she simply backs out the door and disappears, and Alex can practically hear her mortification.

Lena turns her head to look at her, and Alex turns hers. Slowly, like she’s not sure if Alex is going to back away, Lena leans forward and drops a kiss to Alex’s bare shoulder and Alex lets her smile soften.

When Lena pulls back, relief is in her eyes and Alex should be concerned about a lot of things.

But she’s just not.

 


End file.
